i'm a beginner, need some help!

Hello James, and welcome to Chordie!

Both setups look like very good value for the money, and for something to start out with, you're probably safe with either one. In general the BOSS Katana will give a better scope of clean tones (country, blues, etc.), while the Marshall MG would be the better choice for distorted / over-driven tones (rock, metal, etc.). Both are very highly rated for decent quality, entry-priced amps.

I don't know much about the Harley-Benton line of guitars, but the 450 does have the push/pull switching, which allows you to play with either a finer single-coil sound (like a Telecaster or a Stratocaster), or the more full humbucker sound (like a Les Paul or a Gibson SG). Makes it a bit more versatile, but as BGD said, a lot depends on what type of music you prefer.

As your interest and ability grows, you may at some point look at delving into some higher end gear. And by then you'll have a much better idea of what sounds & features you prefer, and which equipment is best suited to your tastes.

Wishing you the very best as you enjoy learning guitar!

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